This invention relates to an exhaust pipe for an automobile or a motorcycle, particularly to one simple in assembling, possible to keep firm all the time and having good effect of muffling.
A known conventional exhaust pipe, as shown in FIGS. 5 and 6, includes an outer pipe 10 fixedly fitted with an inner pipe 20 inside. An air intake pipe 101 and an air outlet pipe 102 with a comparatively small diameter positioned at two opposite ends of the outer pipe 10 and respectively communicating with the front and the rear ends of the inner pipe 20. Further, the inner pipe 20 has numerous through holes 201 bored around its pipe wall and has its outer circumference wound smoothly by galvanized iron strings 30. Then, muffling cotton 40 is filled in a space between the outer pipe 10 and the galvanized iron wires 30.
In using, exhausted gas flowing out of an automobile or a motorcycle first enters the air intake pipe 101 of the outer pipe 10, then goes through small gaps between the through holes 201 and the galvanized iron strings 30 of the inner hole 20, and, finally gets to the muffling cotton 40, thus, attaining an effect of muffling. However, the aforesaid galvanized iron strings used in the conventional exhaust pipe usually give rise to the following defects.
1. In the process of manufacturing, the galvanized iron strings 30 have to be wound around the inner pipe 20 slowly and smoothly, taking much time and labor.
2. When the galvanized iron strings 30 are wound around the inner pipe 20, small gaps among them have to be preset in order to let exhausted gas easily get to the muffling cotton 40. But, actually, the galvanized iron strings 30 can hardly be wound very smoothly and accurately, causing the small gaps left too few or too small, exhausted gas fails to get to the muffling cotton 40, thus lowering muffling effect.
3. After used for a period of time, the galvanized iron wires 30 are possible to become loosened and pushed backward due to a flowing force of a great amount of exhausted gas.
4. After used for a long time, the galvanized iron wires 30 are liable to be burnt out by the high temperature of exhausted gas.
5. The galvanized iron strings are likely to fall off after used for long.
6. Some exhausted oil gas occasionally flowing out of an automobile or a motorcycle mostly flows out through the inner pipe 20 because the small gaps between the galvanized iron strings 30 of the inner pipe 20 are too few and too small, polluting the environment.
This invention has been devised to offer an exhaust pipe for an automobile or a motorcycle, including an outer pipe fixedly fitted with an inner pipe inside. An air intake pipe and an air outlet pipes with a comparatively small diameter of the outer pipe are respectively provided to communicate with the front and the rear end of the inner pipe. Further, the inner pipe has a great many through holes bored around its pipe wall and the outer pipe has muffling cotton filled inside.
The feature of the invention is an intermediate pipe fitted around the inner pipe and having a great number of through holes around pipe wall, with a fixed gap formed between the inner and the intermediate pipes and a muffling cotton filled in between them. Such a design is easy to assemble, capable to keep firm and achieve good effect of muffling.